Peng Gong

Encorafenib (LGX818), a potent BRAF inhibitor, induces senescence accompanied by autophagy in BRAFV600E melanoma cells

Encorafenib (LGX818) is a new-generation BRAF inhibitor that is under evaluation in clinical trials. However, the underlying mechanism remains to be elucidated. Here we show that LGX818 potently decreased ERK phosphorylation and inhibited proliferation in BRAFV600E melanoma cell lines. Moreover, LGX818 downregulated CyclinD1 in a glycogen synthase kinase 3β-independent manner and induced cell cycle arrest in the G1 phase, Surprisingly, LGX818 triggered cellular senescence in BRAFV600E melanoma cells, as evidenced by increased β-galactosidase staining, while no appreciable induction of apoptosis was detected, as determined by Annexin V and propidium iodide staining and immunoblot analysis of caspase-3 processing and poly (ADP-ribose) polymerase cleavage. Increased p27KIP1 expression and retinoblastoma protein activation were detected during LGX818-induced senescence. Additionally, inhibition of dual-specificity tyrosine phosphorylation-regulated kinase 1B by AZ191 reversed LGX818-induced CyclinD1 turnover and senescence. Interestingly, autophagy is triggered through inhibition of the mTOR/70S6K pathway during LGX818-induced senescence. Moreover, autophagy inhibition by pharmacological and genetic regulation attenuates LGX818-induced senescence. Notably, combining LGX818 with autophagy modulators has anti-proliferative effect in LGX818-resistant BRAF mutant melanoma cells. Altogether, we uncovered a mechanism by which LGX818 exerts its anti-tumor activity in BRAFV600E melanoma cells.

New Insight into Ki67 Expression at the Invasive Front in Breast Cancer

Purpose To investigate the distribution of Ki67+ cells in breast cancer in relation to clinical-pathological parameters and prognosis. Materials and Methods Ki67 expression status was detected in 1,086 breast cancer specimens using immunohistochemistry staining and examining the relationship between the Ki67+ cells location. Subsequently, clinical-pathological parameters and prognosis were determined. Results In total, Ki67 protein expression was found in 781 (71.92%) of the 1,086 breast cancer specimens. Among the 781 Ki67+ cases, 461 were defined as diffuse type and 320 were defined as borderline type. After universal correlation analysis, significant differences were observed in age, histological grade, metastatic nodes, postoperative distant metastasis, and molecular subtype between Ki67+ and Ki67− cases (Pu200a=u200a0.01, 0.001, 0.001, 0.001, and 0.001, respectively). After subgroup analysis, the borderline cases were found to be characterized by a high distant metastasis rate compared to the diffuse cases as well as the Ki67− cases (Pu200a=u200a0.001). No differences were observed between diffuse type or Ki67− cases (Pu200a=u200a0.105). Multivariate analysis showed that age, tumor size, histological grade, lymph node metastasis, molecular subtype, and the Ki67 distribution pattern were observed to be related to postoperative distant metastasis (all P<0.05). Furthermore, borderline type was shown to attain a significantly more distant bone and liver metastasis and worse disease-specific survival than the other types (Pu200a=u200a0.001). In the Cox regression test, the Ki67 distribution pattern was detected as an independent prognostic factor (Pu200a=u200a0.001). Conclusion The distribution pattern of Ki67 may be a new independent prognostic factor for breast cancer.

Pancreaticogastrostomy versus pancreaticojejunostomy reconstruction after pancreaticoduodenectomy: a meta-analysis of randomized controlled trials

AbstractPurposeWe conducted this meta-analysis to establish whether pancreaticogastrostomy (PG) or pancreaticojejunostomy (PJ) is the better method of reconstruction for reducing the risk of postoperative pancreatic fistula (POPF).MethodsThis study involved a systematic article search and review of published randomized controlled trials (RCTs) comparing PG vs. PJ after pancreaticoduodenectomy (PD). Cochrane’s risk of bias-assessing tool was used to assess the quality of included studies. The fixed-effect model, random-effect model, and subgroup analysis were performed for the sensitivity analysis.nResultsSix RCTs reporting data on 998 patients were included. The incidence of POPF was lower in the PG group (risk ratio, RRxa0=xa00.65, 95xa0% CI 0.43–0.97, Pxa0=xa00.03), but there was no significant difference in delayed gastric emptying, intra-abdominal fluid collection, biliary fistula, wound infection, postpancreatectomy hemorrhage, overall postoperative complication, or postoperative mortality between the procedures.ConclusionsThis meta-analysis shows that PG is superior to PJ for reducing the incidence of POPF, but there were no differences in other complications or mortality. Therefore, it may be considered as an alternative to PJ and further RCTs are needed to prove our findings.

Bafilomycin A1 induces caspase-independent cell death in hepatocellular carcinoma cells via targeting of autophagy and MAPK pathways.

Hepatocellular carcinoma (HCC) is refractory to chemotherapies, necessitating novel effective agents. The lysosome inhibitor Bafilomycin A1 (BafA1) at high concentrations displays cytotoxicity in a variety of cancers. Here we show that BafA1 at nanomolar concentrations suppresses HCC cell growth in both 2 dimensional (2D) and 3D cultures. BafA1 induced cell cycle arrest in the G1 phase and triggered Cyclin D1 turnover in HCC cells in a dual-specificity tyrosine phosphorylation-regulated kinase 1B (DYRK1B) dependent manner. Notably, BafA1 induced caspase-independent cell death in HCC cells by impairing autophagy flux as demonstrated by elevated LC3 conversion and p62/SQSTM1 levels. Moreover, genetic ablation of LC3 significantly attenuated BafA1-induced cytotoxicity of HCC cells. We further demonstrate that pharmacological down-regulation or genetic depletion of p38 MAPK decreased BafA1-induced cell death via abolishment of BafA1-induced upregulation of Puma. Notably, knockdown of Puma impaired BafA1-induced HCC cell death, and overexpression of Puma enhanced BafA1-mediated HCC cell death, suggesting a role for Puma in BafA1-mediated cytotoxicity. Interestingly, pharmacological inhibition of JNK with SP600125 enhanced BafA1-mediated cytotoxicity both in vitro and in xenografts derived from HCC cells. Taken together, our data suggest that BafA1 may offer potential as an effective therapy for HCC.

Superparamagnetic iron oxide magnetic nanomaterial-labeled bone marrow mesenchymal stem cells for rat liver repair after hepatectomy.

BACKGROUNDnSuperparamagnetic iron oxide magnetic nanomaterials (SPIO) are tracers used for treatment of central nervous and cardiovascular system complications in animal models. The present study investigated survival and proliferation of SPIO-labeled bone marrow mesenchymal stem cells (BMSCs) to determine their potential therapeutic value in liver repair.nnnMETHODSnSurface antigens of BMSCs were measured using flow cytometry. BMSCs viability, growth curve, and SPIO (0-100 μg/mL) labeling rate were evaluated using trypan blue staining, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), and Prussian blue staining, respectively. SPIO-labeled BMSCs were transplanted via liver or spleen injection in rats undergoing 70% hepatectomy. Distribution of SPIO-labeled BMSCs in liver and spleen, and liver repair were evaluated by magnetic resonance imaging (MRI), and serum alanine aminotransferase, aspartate aminotransferase, albumin, and total bilirubin levels.nnnRESULTSnCD29(+)/CD90(+)/CD45(-) BMSCs were successfully isolated from rats. Labeling rate of SPIO in 25 μg/mL was 94.9%. SPIO labeling did not affect BMSCs survival and proliferation. MRI showed that BMSCs colonized in the liver, whether via spleen or liver injection. Serum levels of alanine aminotransferase, aspartate aminotransferase, and total bilirubin in the transplanted rats were significantly lower than in the hepatectomy group at days 1, 3, and 7 after hepatectomy (all P < 0.05), whereas serum albumin levels were significantly higher in the transplanted rats on posthepatectomy day 3 (both P < 0.05). These indicators were not significantly different between the spleen and liver injection approaches.nnnCONCLUSIONSnBMSCs transplantation via liver or spleen injection could significantly accelerate liver healing. In vivo MRI of SPIO-labeled BMSCs can be used to trace real-time liver healing during clinical treatment after hepatectomy.

Clinical, pathological and prognostic characteristics of gastroenteropancreatic neuroendocrine neoplasms in China: a retrospective study

BackgroundGastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are rare neuroendocrine tumors, and lack of data in Asian populations especially in China. The aim of this retrospective study was to assess the clinical, pathological and prognostic characteristics of GEP-NENs in China.MethodsWe collected clinical and pathological data of 168 patients diagnosed with GEP-NENs and treated at the First and Second Affiliated Hospitals of Dalian Medical University between January 2003 and December 2012. Kaplan-Meier method and log rank analysis was used to analyze the prognostic significance of clinical and pathological characteristics.ResultsMean age was 51.83u2009±u200914.03 and the male-to-female ratio was 1.5:1. Primary sites were the rectum (58.93%), pancreas (13.69%), stomach (9.52%), duodenum (5.36%), colon (4.76%), appendix (4.76%), ileum (2.38%) and jejunum (0.60%). Most patients (95.83%) presented non-functional tumors with non-specific symptoms such as abdominal or back pain (29.17%) and gastrointestinal bleeding (25.60%). Based on the 2010 World Health Organization (WHO) classification, patients were diagnosed with neuroendocrine tumor (NET) (24.40%) or neuroendocrine carcinoma (NEC) (7.14%). The estimated mean survival was 8.94u2009±u20090.28xa0years (95% CI: 8.40-9.48). Male gender, young age, small tumor size and NET tumor type were favorable prognostic factors.ConclusionChinese GEP-NENs patients present characteristics that are similar to American and European patients. However, there is an urgent need to establish a national database for understanding the clinical and epidemiological features of GEP-NENs in China.

Hepatitis B virus X protein in the proliferation of hepatocellular carcinoma cells.

Hepatocellular carcinoma (HCC) is one of the most common and deadly malignant neoplasms worldwide. Chronic hepatitis B virus (HBV) infection is closely associated with the occurrence of HCC. The HBV genome encodes a ubiquitous transactivator, termed the HBV X protein (HBx), that is essential for HBV replication in vivo. HBx is involved in multiple steps of carcinoma development. Even in the preneoplastic stage, HBx acts as a tumor promoter. HBx participates in several mechanisms that have been linked to cell proliferation, including gene transcription, cell cycle regulation, and several signaling pathways. Moreover, HBx mutants, especially those with mutations in the COOH-terminal end, have been implicated in hepatocarcinogenesis. Therefore, therapeutic strategies targeting HBx could be effective at multiple stages of HCC development, even as early as the preneoplastic stage.

Better operative outcomes achieved with the prone jackknife vs. lithotomy position during abdominoperineal resection in patients with low rectal cancer

BackgroundLithotomy (LT) and prone jackknife positions (PJ) are routinely used for abdominoperineal resection (APR). The present study compared the clinical, pathological, and oncological outcomes of PJ-APR vs. LT-APR in low rectal cancer patients in order to confirm which position will provide more benefits to patients undergoing APR.MethodsThis is a retrospective study of consecutive patients with low rectal cancer who underwent curative APR between January 2002 and December 2011. Patients were matched 1:2 (PJ-APRu2009=u200974 and LT-APRu2009=u200937 patients) based on gender and age. Perioperative data, postoperative outcomes, and survival were compared between the two approaches.ResultsHospital stay was shorter with PJ-APR compared with LT-APR (Pu2009<u20090.05). Compared with LT-APR, duration of anesthesia (234u2009±u200950.8 vs. 291u2009±u200969xa0min, Pu2009=u20090.022) and surgery (183u2009±u200944.8 vs. 234u2009±u200960xa0min, Pu2009=u20090.016) was shorter with PJ-APR, and estimated blood losses were smaller (549u2009±u2009218 vs. 674u2009±u2009350xa0mL, Pu2009<u20090.001). Blood transfusions were required in 37.8% of LT-APR patients and in 8.1% of PJ-APR patients (Pu2009<u20090.001). There was no difference in the distribution of N stages (Pu2009=u20090.27). Median follow-up was 47.1 (13.6–129.7) months. Postoperative complications were reported by fewer patients after PJ-APR compared with LT-APR (14.9% vs. 32.4%, Pu2009=u20090.030). There were no significant differences in overall survival, disease-free survival, local recurrence, and distant metastasis (Pu2009>u20090.05).ConclusionsThe PJ position provided a better exposure for low rectal cancer and had a lower operative risk and complication rates than LT-APR. However, there was no difference in rectal cancer prognosis between the two approaches. PJ-APR might be a better choice for patients with low rectal cancer.

Effect of bone marrow mesenchymal stem cells on hepatocellular carcinoma in microcirculation.

This study aims t explore the effect and application of bone marrow mesenchymal stem cells (BMSCs) on hepatocellular carcinoma in microcirculation by observing the angiogenesis of hepatocellular carcinoma in transplanted area. BMSCs were isolated and cultured primarily using the method of whole bone marrow culture and identifying surface antigens of third-generation bone marrow-derived mesenchymal stem cells using flow cytometry. Hepatoma cells cultured with BMSCs-conditioned medium (BMSCs-CM) were assayed using the cell proliferation rate of the MTT method. Nude mice were divided into control group (group A), BMSCs cell transplantation group (group B), HepG-2 cell group (group C), and combined BMSCs and HepG-2 cell cotransplanted group (group D). The result showed that the microvascular density was not significantly different in groups A and B. However, the microvascular density at 14xa0days was higher than 0xa0day in group C (Pu2009<u20090.05). In group D, the microvascular density at 14xa0days was higher than that of 7 and 0xa0days (Pu2009<u20090.05) and 7xa0days was higher than 0xa0days (Pu2009<u20090.05). It was showed that the microvascular density did not get significant difference at 0 and 7xa0days in the four groups (Pu2009>u20090.05). But the microvascular density of group C was higher than groups A and B at 14xa0days (Pu2009<u20090.05), group D was higher than groups A and B at 14xa0days (Pu2009<u20090.05) and group D was higher than group C at 14xa0days (Pu2009<u20090.05). BMSCs could promote the growth of microvascular in hepatoma cells in a transplanted area.

Tumor suppressor Spred2 interaction with LC3 promotes autophagosome maturation and induces autophagy-dependent cell death

The tumor suppressor Spred2 (Sprouty-related EVH1 domain-2) induces cell death in a variety of cancers. However, the underlying mechanism remains to be elucidated. Here we show that Spred2 induces caspase-independent but autophagy-dependent cell death in human cervical carcinoma HeLa and lung cancer A549 cells. We demonstrate that ectopic Spred2 increased both the conversion of microtubule-associated protein 1 light chain 3 (LC3), GFP-LC3 puncta formation and p62/SQSTM1 degradation in A549 and HeLa cells. Conversely, knockdown of Spred2 in tumor cells inhibited upregulation of autophagosome maturation induced by the autophagy inducer Rapamycin, which could be reversed by the rescue Spred2. These data suggest that Spred2 promotes autophagy in tumor cells. Mechanistically, Spred2 co-localized and interacted with LC3 via the LC3-interacting region (LIR) motifs in its SPR domain. Mutations in the LIR motifs or deletion of the SPR domain impaired Spred2-mediated autophagosome maturation and tumor cell death, indicating that functional LIR is required for Spred2 to trigger tumor cell death. Additionally, Spred2 interacted and co-localized with p62/SQSTM1 through its SPR domain. Furthermore, the co-localization of Spred2, p62 and LAMP2 in HeLa cells indicates that p62 may be involved in Spred2-mediated autophagosome maturation. Inhibition of autophagy using the lysosomal inhibitor chloroquine, reduced Spred2-mediated HeLa cell death. Silencing the expression of autophagy-related genes ATG5, LC3 or p62 in HeLa and A549 cells gave similar results, suggesting that autophagy is required for Spred2-induced tumor cell death. Collectively, these data indicate that Spred2 induces tumor cell death in an autophagy-dependent manner.